I am a bit confused. I am trying to correct defects manually but I am not sure which voxels must be corrected.

I am attaching 3 pictures containing the right hemisphere with the defects loaded and a specific saved point at each view. I have tried following the instructions of the tutorial, but I can't understand what's wrong with the saved point. The images are quite similar in the few slices up and down. Similar issues are involved in most of the defects shown.

Is there a possibility I did something wrong? Or is there anywhere else besides the tutorial to read more about this?